Temperature testing chamber



June 13, 1950 1 A BREWSTER 2,510,952

TEMPERATURE TESTING CHAMBER Filed June 30, 1944 if F`IG.3

o INVENTOR. LESLIE ABREWSTUQ ATTO/@Nif tions.

Patented June 13, 1950 UNITED STATES PATENT OFFICE (Granted under theact of March 3, 1883, as amended April 3i), 1928; 370 0. G. 757) 3`Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

The invention to be hereinafter described relates to air mixer for heattesting cabinets.

It has long been common practice to test the effects of varying degreesof temperature or heat upon given material, manufactured articles,equipment, etc. For this purpose, heat testing cabinets have beendevised of various construc- Frequently the cabinet comprises severalintercommunicating compartments or chambers, a circulating device forcausing air flow through such compartments and a control device for pronportioning or otherwise regulating the air flow through thecompartments. Some such cabinets also include an air heater and anautomatic regulator for the heater. Many of these cabinets, asheretofore constructed, are unnecessarily complicated, correspondinglyeXpensive and proportionately inefficient. Many of them flow a currentof warm air directly on the coolant to lower the air temperature. Theresult of that is a great waste of the coolant and too sudden drop inthe temperature of the heated air, making regulation difficult. Alsosudden variations in temperature may be damaging to the materials beingtested. Such sudden changes are very likely to be damaging to the testcabinets. Even when there is not that damaging effect to the materialsbeing tested, the relatively sudden changes in temperature resultingmake control difficult and may cause uncertain, inaccurate andunreliable calculations and determinations so that the tests are of lessvalue than they should be.

'Ihe present invention avoids the above and other objections andprovides a simple, enicient, compact and low cost testing cabinet of fewparts in which the air flow control is simple and eilicient and no hotair current is permitted directly over and across the coolant.

In order to more clearly disclose the construction, operation and use ofthe invention reference should be had to the accompanying drawingsforming part of the present application.

Throughout the several figures of the drawings like reference charactersdesignate the same parts in the different views.

In the drawings;

Fig. 1 is a front view of the cabinet, closed;

Fig. 2 is a horizontal cross section on line 2-2 of Fig. 3; and

Fig. 3 is a central vertical cross section.

A preferred construction comprises a box like cabinet body i adequatelyheat insulated relatively to the uses to which it is to be put. Thisbody is divided into three intercommunicating chambers 2, 3 and 4respectively.

Chamber 2 is the cold chamber in which is placed a coolant such as DryIce. Any other suitable coolant, refrigerant or refrigerating deviceInay be used, adequate for the purposes for which the cabinet is to beused. Any such material or device should be, and logically is, disposedin the upper part of the chamber, a shelf, bracket or similar support 5on one wall of the chamber providing a seat in extension of the top wallof the hot air chamber 3. In this arrangement, the Dry Ice or othercooling agent bridges the space between 5 and. the top of the horizontalbranch or" 3. Preferably a heavy screen, grid, or other open-work plateor like device not here shown or further described, bridges the spacemmediately below the cooling means and acts as additional support. Thisis particularly desirable where ice or Dry Ice is used. As such coolantsdecrease in size they would eventually, drop through between 5 and theend of chamber 3 into the lower part of chamber 2 where they would be ofleast eiliciency. Such a grid is, therefore, desirable .but not anessential part of this application.

In the lower part of chamber 2 below the refrigerant or cooling meansand `below the hot air chamber 3 is journaled a fan extending into anopening in the lower part of wall 'i which separates chambers 2 and 4.

The hot air chamber 3 between chambers 2 and A, in the preferred form ofthe invention, is substantially L-shaped in vertical cross section, thelower outer end of the L opening into the upper part of the lowerportion of the cold chamber 2 directly beneath the support for thecooling or reirigerating means. This chamber 3 comprises the twoparallel, spaced, L-shaped partition walls 3 and 9 extending from frontto rear of the cabinet, those cabinet wall portions between 8 and 5icompleting that chamber. Or, of course, charnber 3 may be made as acomplete unit with end walls and insertable as one piece. Walls 8 and 9are provided with circulation openings l@ and I l, respectively, for thelow of test chamber air from chamber1 4 simultaneously into 3 and 2,exclusively into 2 or exclusively into 3, according to circumstances andas desired. Openings IG and H, preferably, extend the full length ofwalls 8 and 9, from front to rear of the cabinet. However, such openingsmay or may not be continuous throughout their lengths as may beindividilally desired. In the cabinets so far actually constructed, theyare continuous. As shown, in the preferred construction, openings liland li are aligned. Between openings le and il, in 3, is journaled,either in the end walls of S or in the walls of the cabinet, acylindrical valve i2 so proportioned that it may completely close eitheropening lll or il or the upper portion of chamber 3.

The normal position or" l2 is as shown in the cross sectional view. Inthat position, air circulated by fan 5 through chamber 'li passesthrough opening lil in wall 'e and into chamber 3. Due to the positionoi valve i2, part oi the flow will pass downwardly in chamber '-3 andthe remainder will pass into the upper part o the cold chamber 2 above,and down over the dry ice or other coolant or rerigerating medium ordevice, and thence into the lower part o chamber .2 for-recirculation byfan 6. And, as will be clear, `the air passing down in chamber 3 willalso flow into the lower part of chamber 2, the two flows mixing as theyare fed for-ward by fan 6 into chamber e.

Within chamber r3 and in the downward path cfiow therethrough is asuitable resistance heaterA i3 of well known type.

Within chamber d is a well known type oi standard thermostatic heatcontrol device hi. It

is -iconnected in usual and well Known manner in 'thecircuit oi heateri3 to automatically turn on or orf the heating current. These devicesand their connections and interconnections are all well :known to thoseskilled in the art and need no further illustration or description here.

The axis or shaft I5 of vaive l2 is extended through the front wall ofthe cabinet and provided with a pointer or other device it cooperatingwith -a suitable dial plate il. Valve l2, in originally assembiing thecabinet, is so Set that its vrelative control positions will beindicated on the dial by the pointer, the pointer also constituting -ahandle for manipulating the valve. For instance, in the presentconstruction, the dial could readily show cold, hot, intermediate andclosed.

And, of course, it may be readily graduated to indicate fractional orsmall movements in one Vdirection or the other. In that arrangement,cold could indicate that valve l2 would be set to direct either all airnow through l and l l and the cold chamber 2 and none through heatingchamber 3 or :agconsiderably greater part through it and l l :and 2 thanthrough 3. In the same arrangement, hot could indicate, similarly, aposition of valve i2 directing all or most of the flow through chamber3. In like manner, intermediate could Vindicate a valve positionYdirecting approximately equal portions yof the air from chamber ithrough t and 2. This position is illustrated in Fig. 3. Finally, closedcould indicate a valve position completely closing mand cutting off'chamber il `from 2 and 3, permitting opening of chamber 2 for renewingrefrigerant or replacing, repairing, etc. the rer-igerating device. Inthat case, the temperature in the testing chamber d will not beappreciably affected during opening oi cham- Y vber 2.

`Manipulate valve l2 until the thermostat I4 shows the temperature in sbeing maintained constant. When that point is reached, place in the testchamber the material or article to be tested and leave it thepredetermined period of the test.

The themostat and valve, as set, will maintain the temperature constant.

By this construction-and arrangement hot air from chamber 3 never iiowsdirectly onto the coolant or refrigerator or through the cold chamber 2.The only air that ows into that chamber is from the test chamber whichis considerably lower in temperature.

By this construction and arrangement neither the hot air from chamber 3nor the cold air from chamber 2 goes directly into the test chamberInstead both are intimately mixed by fan 6 .and delivered as a mixturewith temperature intermediate between that or the two and approximatelythat of the test chamber. This gives a far more uniform condition inchamber d and avoids possible sharp drops or yrises in temperature inthat chamber.

it is thought that the construction, operation use of the invention willbe clear from the preceding detailed description.

Many changes may be made in the construction, arrangement anddisposition of the various parts of the invention and in the materialsused therein, within the scope of the appended claims without in any waydeparting from the field of the invention and it is meant yto includeallsuch within this application wherein only one preferred iorm has beendisclosed by way of illustration and with no thought or intention to, inany regree, limit the invention thereby.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

l. A testing cabinet comprising, in combination, a testing chamber', acooling chamber, a heating chamber extending from the -front through tothe rear oi said cabinet between said testing and cooling chambers, saidheating chamber being provided with aligned openings for the flow oi airfrom said testing chamber into said 'heating chamber and across saidheating chamber into said cooling chamber, means for circulating airfrom said heating and cooling chambers into said testing chamber, and.unitary valve means having a plurality of positions for regulating saidair flow from said testing `chamber, said valve means being selectivelyand fprogressiveiy variable from a first position in which all the airflowing from said testing chamber is cut-ofi, to a second position inwhich all the air hows from said testing chamber. intosaid coolingchamber, to a third positionl'in which all ithe air ows from saidtesting chamber linto said heating chamber, said vaive means bei-ngvariably positionable between the aforementioned positions forproportioning the nowoi Eair 'from said testing chamber within thelimits set by the aforesaid positions.

2. A testing cabinet comprisinggin combination, a testing chamber, acooling chamber, Va heating chambereXtendi-ng from the front throught@the rear oi said cabinet between said `testingfand cooling chambers,-said heating 'chamber Kbeing provided with aligned openings i'o'r theflow/of air from said testing chamber into Asaid Vheating chamber andacross saidY heating :chamber into said cooling chamber, said heating vchamber opening into the ylower portionv of said cooling chamber, saidtesting chamber having-an opening `for receiving the combined output ofsaid heating and cooling chambers, means positioned in said testingchamber opening for circulating the air from said heating and coolingchambers into said testing chamber, and unitary valve means having aplurality of positions for regulating the air ilow from said testingchamber. said valve means being selectively and progressively variablefrom a first position in which all the air flowing from said testingchamber is cutoff, to a second position in which all the air flows fromsaid testing chamber into said cooling chamber, to a third position inwhich all the air iiows from said testing chamber into said heatingchamber, said valve means being variably positionable between theaforesaid positions for proportioning the flow of yair from said testingchamber Within the limits set by the aforesaid positions.

3. A testing cabinet comprising, in combination, a testing chamber, acooling chamber, a heating chamber extending from the front through tothe rear of said cabinet between said testing and cooling chambers, saidheating chamber being provided with aligned openings for the 110W of airfrom said testing chamber into said heating chamber and across saidheating chamber into said cooling chamber, said testing chamber havingan opening for receiving the combined output of said heating and coolingchambers, means positioned in said testing chamber opening forcirculating the air from said heating and cooling chambers into saidtesting chamber, means Within said cooling chamber positioned above theopening into said testing chamber for supporting a cooling medium, andunitary valve means having a plurality of positions for regulating theair flow from said testing chamber, said valve means being selectivelyand progressively variable from a first position in which all the airowing from said testing chamber is cut-off, to a second position inwhich all the air flows from said testing chamber into said coolingchamber, to a third position in which all the air flows from saidtesting chamber into said heating chamber, said Valve means beingvariably positionable between the aforesaid positions for proportioningthe ilow of air from said testing chamber Within the limits set by theaforesaid positions.

LESLIE A. BREWSTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,609,964 Roby Dec. 7, 19261,859,613 Bailey May 24, 1932 1,904,697 Ruppert Apr. 18, 1933 2,254,185Newton Aug. 26, 1941 2,234,764 Parks June 2, 1942 2,359,796' RussellOct. 10, 1944 2,373,333 St, Onge Apr. 10, 1945

